% Copyright 2020 Makani Technologies LLC
%
% Licensed under the Apache License, Version 2.0 (the "License");
% you may not use this file except in compliance with the License.
% You may obtain a copy of the License at
%
%      http://www.apache.org/licenses/LICENSE-2.0
%
% Unless required by applicable law or agreed to in writing, software
% distributed under the License is distributed on an "AS IS" BASIS,
% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
% See the License for the specific language governing permissions and
% limitations under the License.

function [ppp] = mrp_mult(pp, p)
n = (1 - p'*p)*pp + (1 - pp'*pp)*p - 2*cross(pp, p);
d = 1 + pp'*pp * p'*p - 2*pp'*p;
ppp = n / d;